Dijkstra Algorithm using STL Vector with STL Priority Queue

#include<vector>
#include<list>
#include<iostream>
#include<queue>
using namespace std;


#define SIZE 100
#define INF 100000


struct pq
{
int cost,node;
bool operator<(const pq &b)const
{
return cost>b.cost;    // Min Priority Queue
}
};
vector<pq>adj[SIZE];


vector<int> Dijkstra(int source,int nodes)
{
priority_queue<pq>Q;
vector<int>dist;
pq U,V;
int i;


for(i=0;i<nodes;i++)
{
dist.push_back(INF);
}
dist[source]=0;
V.node=source;
V.cost=0;
Q.push(V);
while(!Q.empty())
{
U=Q.top();
Q.pop();
for(i=0;i<adj[U.node].size();i++)
{
if(dist[U.node]+adj[U.node][i].cost<dist[adj[U.node][i].node])
{
dist[adj[U.node][i].node]=dist[U.node]+adj[U.node][i].cost;
V.node=adj[U.node][i].node;
V.cost=dist[adj[U.node][i].node];
Q.push(V);
}
}
}
return dist;
}
int main()
{
int nodes,edges,i,u,v,cost,source;
pq V;
vector<int>dist;


while(scanf("%d %d",&nodes,&edges)==2)
{
for(i=0;i<nodes;i++)
{
adj[i].clear(); //clear adj vector
}
for(i=0;i<edges;i++)
{
scanf("%d %d %d",&u,&v,&cost);
V.cost=cost;
V.node=v;
adj[u].push_back(V);
/*V.node=u; //For Bidirectional Edges active this comments
adj[v].push_back(V);*/
}
scanf("%d",&source);
dist=Dijkstra(source,nodes);
for(i=0;i<nodes;i++)
{
cout<<dist[i]<<" ";
}
cout<<endl;
}


return 0;
}
/*
Input:
6 9
0 1 4
0 2 2
1 2 1
1 3 5
2 3 8
2 4 10
3 5 6
3 4 2
4 5 3
0
Output:
Shortest Path All the Node Frome Source:
For Bidirectional:
0
0 3 2 8 10 13
For Directional:
0
0 4 2 9 11 14
*/